Material for resist protective film for immersion lithography

Abstract

To provide a resist protective film material for immersion lithography. An alkali soluble resist protective film material for immersion lithography, which comprises a polymer (F) containing repeating units (F U ) formed by polymerizing a polymerizable compound (f m ) having a fluorine-containing bridged cyclic structure. For example, repeating units (F U ) are repeating units formed by polymerizing a compound (f) selected from the group consisting of the following formulae (f1) to (f4) (R F represents H, F, a C 1-3 alkyl group or a C 1-3 fluoroalkyl group, and X F represents F, OH or CH 2 OH.)

1 . A material for an alkali soluble resist protective film for immersion lithography, which comprises a polymer (F) containing repeating units (F U ) formed by polymerization of a polymerizable compound (f m ) having a fluorine-containing bridged cyclic structure. 
   
   
       2 . The material for a resist protective film for immersion lithography according to  claim 1 , wherein the polymerizable compound (f m ) is a compound (f) selected from the group consisting of compounds represented by the following formulae (f1), (f2), (f3) and (f4): 
     
       
         
         
             
             
         
       
       wherein the symbols have the following meanings: 
       R F : A hydrogen atom, a fluorine atom, a C 1-3  alkyl group or a C 1-3  fluoroalkyl group, 
       X F : A fluorine atom, a hydroxyl group or a hydroxymethyl group, 
       wherein a fluorine atom in the compound (f) may be substituted by a C 1-6  perfluoroalkyl group or a C 1-6  perfluoroalkoxy group. 
     
   
   
       3 . A polymer for an alkali soluble resist protective film for immersion lithography, which is a polymer (FB) containing repeating units (F U ) formed by polymerization of a polymerizable compound (f m ) having a fluorine-containing bridged cyclic structure and repeating units (B U ) formed by polymerization of a polymerizable compound (b m ) having a hydroxyl group, a carboxyl group, a sulfonic acid group, a sulfonylamide group, an amino group or a phosphoric acid group. 
   
   
       4 . The polymer for a resist protective film for immersion lithography according to  claim 3 , wherein the polymerizable compound (f m ) is a compound (f) selected from the group consisting of compounds represented by the following formulae (f1), (f2), (f3) and (f4): 
     
       
         
         
             
             
         
       
       wherein the symbols have the following meanings: 
       R F : A hydrogen atom, a fluorine atom, a C 1-3  alkyl group or a C 1-3  fluoroalkyl group, 
       X F : A fluorine atom, a hydroxyl group or a hydroxymethyl group, 
       wherein a fluorine atom in the compound (f) may be substituted by a C 1-6  perfluoroalkyl group or a C 1-6  perfluoroalkoxy group. 
     
   
   
       5 . The polymer for a resist protective film for immersion lithography according to  claim 3 , wherein the polymerizable compound (b m ) is a polymerizable compound having a group represented by the formula —C(CF 3 )(OH)—, —C(CF 3 ) 2 (OH) or —C(O)OH. 
   
   
       6 . The polymer for a resist protective film for immersion lithography according to  claim 3 , wherein the polymerizable compound (b m ) is a compound (b) selected from the group consisting of compounds represented by the following formulae (b1), (b2), (b3) and (b4): 
     
       
         
         
             
             
         
       
       wherein the symbols have the following meanings: 
       Q B1 : A group represented by the formula —CF 2 C(CF 3 )(OH)(CH 2 ) m —, a group represented by the formula —CH 2 CH((CH 2 ) n C(CF 3 ) 2 (OH))(CH 2 ) m — or a group represented by the formula —CH 2 CH(C(O)OH)(CH 2 ) m —, 
       m and n: Each independently 0, 1 or 2, 
       R B2 : A hydrogen atom, a fluorine atom, a C 1-3  alkyl group or a C 1-3  fluoroalkyl group, 
       Q B2  and Q B3 : Each independently a C 1-20  (b+1) valent hydrocarbon group, 
       b: 1 or 2, 
       Q B4 : a single bond or a C 1-10  bivalent hydrocarbon group, 
       wherein a fluorine atom may be bonded to a carbon atom in Q B2 , Q B3  or Q B4 . 
     
   
   
       7 . The polymer for a resist protective film for immersion lithography according to  claim 3 , wherein the polymer (FB) is a polymer containing from 1 to 70 mol % of repeating units (F U ) and at least 10 mol % of repeating units (B U ) based on the total amount of repeating units. 
   
   
       8 . The polymer for a resist protective film for immersion lithography according to  claim 3 , wherein the polymer (FB) is a polymer containing from 3 to 15 mol % of repeating units (F U ) and from 85 to 97 mol % of repeating units (B U ) based on the total amount of repeating units. 
   
   
       9 . A composition for forming a resist protective film for immersion lithography, comprising the polymer for a is resist protective film for immersion lithography as defined in  claim 3  and an organic solvent. 
   
   
       10 . A method for forming a resist pattern on a substrate, which is a method for forming a resist pattern by immersion lithography, which comprises sequentially carrying out a step of applying a photosensitive resist material on a substrate to form a photosensitive resist film on the substrate, a step of applying the composition for forming a resist protective film for immersion lithography as defined in  claim 9  on the photosensitive resist film to form a resist protective film layer on the photosensitive resist film, a step of immersion lithography, and a step of development. 
   
   
       11 . An alkali soluble resist protective film composition for immersion lithography, which comprises a polymer (F) containing repeating units (F U ) formed by polymerization of a polymerizable compound (f m ) having a fluorine-containing bridged cyclic structure and a polymer (B) containing repeating units (B U ) formed by polymerization of a polymerizable compound (b m ) having a hydroxyl group, a carboxyl group, a sulfonic acid group, a sulfonylamide group, an amino group or a phosphoric acid group. 
   
   
       12 . The resist protective film composition for immersion lithography according to  claim 11 , wherein the polymerizable compound (f m ) is a compound (f) selected from the group consisting of compounds represented by the following formulae (f1), (f2), (f3) and (f4): 
     
       
         
         
             
             
         
       
       wherein the symbols have the following meanings: 
       R F : A hydrogen atom, a fluorine atom, a C 1-3  alkyl group or a C 1-3  fluoroalkyl group, 
       X F : A fluorine atom, a hydroxyl group or a hydroxymethyl group, 
       wherein a fluorine atom in the compound (f) may be substituted by a C 1-6  perfluoroalkyl group or a C 1-6  perfluoroalkoxy group. 
     
   
   
       13 . The resist protective film composition for immersion lithography according to  claim 11 , wherein the polymerizable compound (b m ) is a polymerizable compound having a group represented by the formula —C(CF 3 )(OH)—, —C(CF 3 ) 2 (OH) or —C(O)OH. 
   
   
       14 . The resist protective film composition for immersion lithography according to  claim 11 , wherein the polymerizable compound (b m ) is a compound (b) selected from the group consisting of compounds represented by the following formulae (b1), (b2), (b3) and (b4): 
     
       
         
         
             
             
         
       
       wherein the symbols in the formulae have the following meanings: 
       Q B1 : A group represented by the formula —CF 2 C(CF 3 )(OH)(CH 2 ) m —, a group represented by the formula —CH 2 CH((CH 2 ) n C(CF 3 ) 2 (OH))(CH 2 ) m — or a group represented by the formula —CH 2 CH(C(O)OH)(CH 2 ) m —, 
       m and n: Each independently 0, 1 or 2, 
       R B2 : A hydrogen atom, a fluorine atom, a C 1-3  alkyl group or a C 1-3  fluoroalkyl group, 
       Q B2  and Q B3 : Each independently a C 1-20  (b+1) valent hydrocarbon group, 
       b: 1 or 2, 
       Q B4 : a single bond or a C 1-10  bivalent hydrocarbon group, 
       wherein a carbon atom in Q B2 , Q B3  or Q B4  may be bonded to a fluorine atom. 
     
   
   
       15 . The resist protective film composition for immersion lithography according to  claim 11 , wherein the polymer (F) is a polymer consisting solely of repeating units (F U ) formed by polymerizing a polymerizable compound (f m ) having a fluorine-containing bridged cyclic structure. 
   
   
       16 . The resist protective film composition for immersion lithography according to  claim 11 , wherein the polymer (F) is a polymer containing repeating units (F U ) formed by polymerizing a polymerizable compound (f m ) having a fluorine-containing bridged cyclic structure and repeating units (B U ) formed by polymerizing a polymerizable compound (b m ) having a hydroxyl group, a carboxyl group, a sulfonic acid group, a sulfonylamide group, an amino group or a phosphoric acid group, and the polymer (F) is a polymer containing from 1 to 25 mol % of repeating units (F U ) and from 75 to 99 mol % of repeating units (B U ) based on the total amount of repeating units. 
   
   
       17 . The resist protective film composition for immersion lithography according to  claim 11 , wherein the polymer (F) is contained in an amount of from 0.1 to 30 mass % based on the polymer (B). 
   
   
       18 . The resist protective film composition for immersion lithography according to  claim 11 , wherein the polymer (F) is contained in an amount of more than 30 mass % and at most 200 mass % based on the polymer (B). 
   
   
       19 . A composition for forming a resist protective film for immersion lithography, comprising the resist protective film composition for immersion lithography as defined in  claim 11  and an organic solvent. 
   
   
       20 . A method of forming a resist pattern on a substrate, which is a method of forming a resist pattern by immersion lithography, which comprises sequentially carrying out a step of applying a photosensitive resist material on a substrate to form a photosensitive resist film on a substrate, a step of applying the composition for forming a resist protective film for immersion lithography as defined in  claim 19  on the photosensitive resist film to form a resist protective film layer on the photosensitive resist film, and a step of an immersion lithography, and a step of development.